Some Keto Diets Could Make This Skin Condition Far Worse, Scientists Warn

People with psoriasis should avoid certain ketogenic diets, scientists who studied its impact on mice have warned.

The low-carb, high-fat diet has grown in popularity in recent years, as research suggests it could help with maintaining a healthy body weight, and control blood sugar levels.

The authors of the new study published in the Journal of Investigative Dermatology highlight it is also thought to have anti-inflammatory properties. Keto has therefore piqued the interest of dermatologists who treat conditions like psoriasis: a chronic autoimmune disease that makes skin cells grow faster than normal. Past research has suggested saturated fat could worsen the symptoms of psoriasis, which causes patches of thick, red skin and scales to develop on the body.

Most followers of the keto diet get up to 30 percent of their calories from protein sources and limit carb-heavy foods to less than 50 grams day—the equivalent of two medium apples. This puts the body in a state of what is known as ketosis, where fatty acids called ketones are produced and used for energy instead of carbohydrates.

The authors of the study, published in the Journal of Investigative Dermatology, investigated how the ketogenic diet might affect mice with a condition similar to psoriasis.

The team put the rodents on an extreme versions of the keto diet—usually only followed by those with treatment-resistant epilepsy. They featured 77 to 80 percent fats, 15 to 25 percent proteins and only 5 to 10 percent carbohydrates.

Researchers found animals who ate a foods heavy in what are known as medium-chain triglycerides (MCTs), particularly when paired with omega-3 fatty acids, saw their skin worsen. Foods like coconut oil, dairy products, and palm kernel oil contain relatively high levels of MCTs, while omega-3 is found in fish oil and foods like flaxseed, chia seeds, and walnuts.

But a well-balanced ketogenic diet featuring mainly long-chain triglycerides did not appear to worsen the skin. These foods include fish, nuts, avocado, as well as olive and soybean oil, and meat.

Roland Lang of Paracelsus Medical University, who co-lead the study, explained ketogenic diets high in MCTs seemed to make the mice express pro-inflammatory proteins called cytokines, and trigger a build-up of white blood cells called neutrophils. This likely made the psoriasis worse, he argued.

"I think most people following a ketogenic diet don't need to worry about unwanted skin inflammation side effects," he said in a statement. "However, patients with psoriasis should not consider a ketogenic diet an adjuvant therapeutic option."

Co-author Barbara Kofler, of the Department of Pediatrics at Paracelsus Medical University, told Newsweek she didnt expect a diet linked to anti-inflammatory to worsen psoriasis.

Kofler went on to highlight that as the study was carried out on animals, it's unclear that the same effect would be seen in humans. Also, the study used a very high fat diet, which humans don't usually follow.

"Our study indicates that people with psoriasis should be careful when considering a ketogenic diet," she said. "The diet should, at least at the beginning, not be supplemented with high amounts of medium chain fatty acids and omega 3 fatty acids."

Patients with psoriasis who change to a ketogenic diet should be monitored "strictly for disease symptoms by a dermatologist," said Kofler.

"In addition dietary advice by a dietitian will also be helpful to implement the diet and ensure proper supply with vitamins and minerals," she suggested.

The study follows a separate piece of research published in the journal JAMA Dermatology earlier in the week which suggested people with psoriasis could be at greater risk of developing or dying of cancer.

Alex Trafford, co-author of the study in the pharmacy department at U.K's Manchester University, told Newsweek on Wednesday: "As with people without psoriasis, making healthy lifestyle changes might lower the risk of cancer."

This article has been updated with comment from Barbara Kofler.